Polylactic acid or Polylactide, abbreviation: PLA is a new type of bio-based and renewable biodegradable material, which is made of starch raw materials proposed by renewable plant resources (such as corn, cassava, etc.). The lactic acid or lactide required for the production of polylactic acid can be obtained through the fermentation, dehydration and purification of renewable resources (starch), and the synthesis of a certain molecular weight polylactic acid through chemical synthesis generally has good biodegradability. After use, it can be completely degraded by microorganisms in nature under specific conditions, and eventually produce carbon dioxide and water, which is very environmentally friendly.